1. The Field of the Invention
The present invention relates to transporting payloads suspended from an aircraft. More specifically, the present invention discloses methods and apparatus for selectively attaching and selectively releasing multiple payloads suspended from an aircraft.
2. The Relevant Technology
Helicopters have long been used to deliver payloads of different size and shape. Traditionally, a cable is suspended from a helicopter having a hook attached to one end of the cable. By attaching the hook to a payload, the helicopter is able to transport the payload to a desired location. Suspending the payload beneath a helicopter permits the helicopter to transport oversized cargo, such as a jeep.
Furthermore, a helicopter is able to deliver the payload to unique and specific locations, such as on top of a building or in rugged terrain, where an airplane could not land. In addition, the use of a suspended cable permits a helicopter to deliver or receive cargo without actually having to land. By lowering the cable, a receiving party can remove or attach a payload to the hook. This is most beneficial with regard to emergency rescues and in delivering payloads in congested areas.
Although there are numerous benefits in using a conventional hook and cable assembly to deliver a payload suspended beneath a helicopter, several shortcomings are also found. For example, using a single cable and hook assembly typically only permits transporting a single payload per flight. Such an assembly necessitates numerous flights, costing both time and money, to deliver multiple payloads which cannot simultaneously be attached to a single hook.
Furthermore, to remove a payload from a conventional hook and cable assembly, either the helicopter must land or the payload must be lowered to the ground and manually removed from the hook. Such processes require both time and the necessity of a receiving party at the unloading location to unload the payload. The necessity of a receiving party to remove a payload is detrimental in an emergency situation where it would be preferable to jettison the payload during flight or where it is desirable to release a payload at a location where there is no receiving party.
In an attempt to alleviate these problems, carrousel hook systems have been made. The carrousel hook systems comprise a frame having a plurality of hooks attached thereto. The frame is suspended from a helicopter by a support cable. Likewise, an electrical cable extends from the helicopter to each of the hooks. By triggering a switch within the helicopter, the hooks can be consecutively opened, thereby releasing the attached loads.
Several problems or shortcomings, however, have also been encountered with the carrousel hook systems. Forces such as the wind and movement of the aircraft can result in rotation of the carrousel frame which in turn applies a torsional force on the support cables and the helicopter. Such a force can damage the cables and the connection to the helicopter. Likewise, the torsional force can affect the navigation ability of the helicopter.
The hooks and the carrousel hook system are designed to operate in a consecutive manner. For example, hook number 4 cannot be opened until hooks 1-3 have been opened. Such a configuration severely limits the ability of the operator to selectively release the attached payloads. It is also difficult for the operator to determine which of the hooks is next to release and if a payload has fully been removed from the hook. Furthermore, such a configuration does not permit all of the payloads to be dropped concurrently.
The current hook systems also do not address some of the general problems in the art. As with all aircraft, helicopters have a load limit. Exceeding the load capacity of a helicopter can affect the navigational ability of the aircraft or result in failure of the aircraft. Current embodiments for transporting cargo suspended from an aircraft provide no means other than manually weighing the cargo before loading to determine the weight of cargo. The ability to always know the weight of the payloads is especially important during repeated rapid loading and unloading of cargo.
In addition, since the payload is suspended beneath the helicopter, it can often be difficult for the pilot using conventional methods to accurately navigate the payload to an exact unloading position. This is especially difficult at night or in congested areas, such as within a jungle.